Automatic surface treating machine



June 7, 966 D. L. CETRANGOLO 3,254,454

AUTOMATIC SURFACE TREATING MACHINE Filed Feb. 24, 1964 5 Sheets-Sheet 1Wfir ATTORNEY June 7, 1966 D. L. CETRANGOLO 3,254,454

AUTOMATIC SURFACE TREATING MACHINE 5 Sheets-Sheet 2 Filed Feb. 24, 1964FIG. 4

FIG. 6

INVENTOR u DOLIVIO L. CETRANGOLO FIG. IO

J1me 1966 D. 1.. CETRANGOLO 3,254,454

AUTOMATIC SURFACE TREATING MAQHINE Filed Feb. 24, 1964 5 Sheets-Sheet 3DOLIVIO L.CETRANGOLO United States Patent Office 3,254,454 AUTOMATICSURFACE TREATING MACHINE Dolivio L. Cetrangolo, E. Roxbury Road,Northfield, Vt. Filed Feb. 24, 1964, Ser. No. 346,927 Claims. (Cl.51-56) This invention relates to the finishing and polishing of thesurface of objects of various kinds including of stone where substantiallabor and skill is involved, as well as to a machine by which the finalfinishing and polishing operations are performed.

The invention relates particularly to a machine having an abrading heador work unit'of a character to be moved over the surface of stone orother hard surfaced objects to be finished and polished, and whichmachine ordinarily is hand operated by a workman to finish and polishthe surface and edges of an object regardless of whether flat,contoured, serpentine or oval.

After a slab of stone such as marble, granite or the like has been sawedor otherwise reduced to desired size, it is necessary to smooth andpolish the slab to provide a finished product. The procedure has been togo over the stone with a relatively thick coarse grinding wheel toremove the high spots on the stone. Then a thinner flexible 7 wheel hasbeen used in the presence of an abrasive which normally is suspended ina fluid such as water, or the like. When all of the marks have beenremoved, the stone is then polished by a felt buffer to bring out thenatural beauty of the stone.

Heretofore, the finishing of the stone has been a laborious task inwhich it hasbeen necessary for an operator to control the movement ofthe grinding and polishing wheels. This has required the undividedattention of the operator to finish one stone at a time and has resultedin fatigue on the part of the operator and lack of uniformity in thefinished product, as well as limiting the output of the operator.

It is an object of the invention to provide a fully automatic machinefor performing the finishing and polishing operations on relatively hardsurfaces, including objects which have coarse surfaces, as well as thosehaving finer surfaces, and which machine can be given a definitepredetermined setting and allowed to operate automatically with only asingle work-man attending a number of machinesto obtain readily,satisfactorily and expeditiously a surface of uniformly high quality atsubstantially lower cost, in a comparatively short time with littlefatigue to the attendant.

.Another object of the invention is to provide a machine which can beeasily and quickly adjusted while in operation without loss of time, andwhich will pause for a predetermined and variable length of time at eachedge or limit of the surface of the work where it is most necessary togive greater time than in the center of the surface being finished.

Other objects and advantages of the invention will be apparent from thefollowing description taken in conjunction with the accompanyingdrawings in which:

FIG. 1 is a perspective illustrating one application of the invention;

FIG. 2, a rear elevation thereof;

FIG. 3, an enlarged transverse section on the line 33 v FIG. 9, anenlarged fragmentary detail section on the line 9-9 of FIG. 1;

FIG. 10, a fragmentary detail elevation illustrating one of theadjustable projections or stops;

FIG. 11, a transverse section on the line 11 11 of FIG. 10;

FIG. 12, a rear elevation of a modified form of the invention; 7

FIG. 13, an enlarged perspective of the driving mechanism of FIG. 12;

FIG. 14, a section similar to FIG. 3 of the modified device of FIG. 12;

FIG. 15, a vertical section on the line 15--15 of FIG. 14;

FIG. 16, a perspective of a modified drive means for the grinding andpolishing wheel; and v FIG. 17, a perspective of a further modified formof drive means for the grinding and polishing wheel.

Briefly stated the finishing and polishing machine of the presentinvention is composed of three basic parts, including: First, a tank inwhich the stone or other hard surfaced object is received and supportedin the presence of water or other fluid; second, a grinding unit withmeans for supporting it for raising and lowering movement and, third,means for guiding the movement of the grinding unit in two generallyhorizontal directions, one at right angles to the other. I a

With continued reference to the drawings, a tank 10 of any desiredmaterial is provided for containing water, light oil, or other fluid. Ablock of stone or other object 11, having a rough surface and roughedges is adapted to be received in said tank to be finished and polishedto sired character, such as with concentric rings or the like is mountedby brackets 13 on a shaft 14 journaled in suitable bearings (not shown)in a housing 15.

On the shaft 14 is a multiple grooved pulley 16 driven from a motor 17through a pulley 18 on the motor shaft and by means of belts 19 drivingthe pulley 16 and the shaft 14 of the floating abrading or grinding heador unit. In finishing and polishing the relatively hard surface of astone or other object, it is necessary that the polishing wheel be movedover the entire surface including the edges where it is necessary to beretained for a longer period of time than over the intermediate area dueto the fact that the diameter of the abrading unit is in contact withthe intermediate portion for a longer period of time. The grinding andpolishing or abrading unit is of the floating head type and is providedwith a yoke 20 attached to the housing 15 and connected by a ball andsocket coupling 21 and a tightening screw 22 to a shaft 23. The shaft 23extends through a fitting 24 and is attached to a platform 25 which inturn is connected to a sleeve 26 slidable on a pipe or tubular member 27mounted on end posts 28. The ends of the tube 27 are provided-'withspaced vertical bars 29 having axles 30 carrying sprockets 31 over whichis mounted a chain 32 having upper and lower horizontal runs, the uppercentral portion of the chain being located around idler sprockets 33mounted on a support 34 fixed to the sleeve 26.

The chain 32 extends between the idler sprockets 33 and over a drivesprocket 35 mounted on the output shaft 36 of a gear box 37. Such gearbox is driven by a pulley 38 by means of a belt 39 and a drive pulley 40mounted on the shaft of a motor 41. The motor 41 is a threephasereversible motor in order to produce the necessary reciprocation of theabrading head. A pair of stops 42 are adjustably mounted in apredetermined position on the chain 32, the adjustability making itpossible to regulate the amount of delay when the direction of movementof the grinding wheel is reversed.

Patented June 7, 1966- As the sprocket 35 rotates the chain 32 will movethrough openings 43 in the posts 28 until one of the adjustable stops 42engages one of the posts, for example, the post 28 at the right in FIG.2. The continued operation of the sprocket 35 by the motor 31 will causethe sleeve 26 and entire platform 25 with its contents to move along thetubular member 27 until one of a pair of limit switches 26', carried oneon each end of the sleeve 26, engages one of a pair of projections 44mounted on sleeves 44 adjustably secured to opposite ends of the tube27. The closing of either of the switches 26' causes the motor 41 toreverse itself and the platform 25 and the grinding head carried with itwill remain stationary until the chain has had time to travel in theopposite direction until the other stop 42 engages the opposite post 28.The sleeves 44 are adjustable to increase the flexibility of operationand normally are spaced apart a distance generally equal to the lengthofthe stone so that the working head will remain on the surface it ispolishing.

A second motor 45 is mounted on the platform 25 and is adapted to drivea gear box 46 having a projecting shaft 47 on which is fixed a crank arm48 with a slot 49 receiving a pivot point or pin 50 and by which aconnecting rod 51 is a reciprocated. The connecting rod 51 has itsremote end connected to a pivot 52, mounted on a bracket 53, fixed tothe reciprocating round rod or shaft 23 which extends through thefitting 24.

The motor 45 causes rotation of the crank arm 48 to producereciprocation of the bracket 53 and the shaft 23 causing the finishingand polishing unit to move transversely of the stone or other hardsurfaced object upon which work is being performed so that in effectthere is a lengthwise and transverse movement of the polishing unit.

The shaft 23 travels a limited amount transversely and the platform 25and sleeve 26 travel lengthwise of the object upon which work is beingperformed. The amount of reciprocation of the shaft 23 can be adjustedbetween certain limits by adjusting the pivot 50 in the slot 49 of thecrank arm 48.

The invention is of such a character that work of various lengths andbreadths, from a very few inches to several feet, can be treated.Differences in the width of the work handled is accommodated by the sizeof the abrasive wheels and the setting of the same for motion in regardto the slab being treated. The amount of movement of the end of theconnecting rod is dependent upon the location of the crankshaft pivotpoint 50. If a small stone is to be polished, an abrasive wheel of adiameter to cover the stone can be provided and the pivoted connectionof i the connection rod will be located as close to the pivot point ofthe crank arm as possible to provide minimum motion of the shaft 23.

Treatment of a curved surface presents no problem due to the fact thatthe surfaces of the members 27 and 26 are circular. This allows the balland socket coupling 21 to permit the operating head to follow thecontour of the surface against which it is operating. The motor 41 andgear box 37 are adapted to move the sleeve 26 along the tubular member27 at a relatively slow rate of speed while the motor 45 and gear box 46with the crank arm 48 will move the shaft 23 and the abrading orpolishing head at a more rapid rate of speed. This causes the abradinghead to move back and forth across the stone many times during eachtraverse of the length of the stone. In view of the operation of theunit in its association with the chain 32 and the stops and limitswitches, grinding action at the opposite ends of the stone will beaccomplished with the grinding head moving transversely while there isno longitudinal movement. Consequently the ends will receive a greateramount of treatment than the mid-portion which is desirable. Due to thelimits of the throw of the crank there also will be a pause of the workunit at opposite ends of its path of travel because the work head movesfaster across the mid-portion of the work than at the edges.

The inner end of the connecting rod 51 and the crank 48 in motiondescribe the circumference of a circle and travel at a constant rate ofspeed. Therefore, the speed of the connecting rod 51 is greater duringthe middle of the stroke than it is at each end, decreasing in rate ofspeed until eventually it stops and reverses direction with graduallyaccelerating speed as it travels toward the middle of the stroke.

The pivotal mounting of the platform 25 on the tube .27 permits raisingand lowering of the work head affording access to the work area and theinsertion and removal of a stone or other object from the tank 10.Raising of the work head is facilitated by means of a post 55 rotatablymounted on a base 56. The post 55 may be an I-beam or of otherconstruction, about which is mounted a pair of spaced yokes or couplingmembers 57 having rollers 58 disposed on one side of the post androllers 59 supported by brackets 59' carried by the yokes 57 on theopposite side of such post. The rollers 58 and 59 bear against oppositesurfaces of the post to reduce friction and permit ready raising andlowering of the couplings. An arm or bracket 60 attaches to the uppercoupling member 57 and has pivoted to its outer end a depending rod orbar 61 having its lower end pivoted to a yoke 62 having diverging legs63 fixed to the housing 15. Beyond its center the arm or bracket 60 issupported by a bracket or brace 64, the lower end of which attaches tothe lower connector 57. The rollers 59 are mounted in upright brackets59' so that they are spaced above the brackets 60 and 64 to maintain afirmer relation with the post 55 on which the assembly is mounted.

In order to raise the arm 60 and the depending bar 61 carried by it, aplatform 65 is provided having one end attached to the brace 64 and theother end attached to a brace 66 mounted on lower bracket 59'. On theplatform 65 is mounted a motor 67 on the shaft of which is a pulley 68which drives a gear box 70 by means of a belt 69. A sprocket 7 1 isfixed to the output shaft of the gear box 70 and drives a chain 72 and asecond sprocket 73 which in turn drives a pinion 74 engaging a rack 75attached to the post 55. The operation of the motor 67 which causes thepinion to travel along the rack may be controlled from a suitablecontrol panel (not shown).

With reference to FIGS. 1215 a modified form of the invention isdisclosed which is used primarily in the bufiing or polishing processalthough it could be used in the grinding process. In this modificationthe vertical bars 29 and sprockets 31 are removed from one end of thedevice and are replaced by a single relatively large sprocket mounted ona shaft 81 rotatably journaled in bearings 82 carried by a platform 83fixed to one of the upright posts 28. The sprocket 80 is adapted toreceive the chain 32 and to drive such chain and the sleeve 26 along thetubular member 27. The sprocket 80 .has a plurality of openings 84 inwhich a pair of pegs 85 and 86 are selectively mounted. In order todrive sprocket 80 a motor 87 is mounted on a platform 88 and is adaptedto drive a gear reduction 89 having output shaft 90 locatedsubstantially along the same axis as the shaft 81. The free end of theoutput shaft 90 is provided with an arm 91 substantially at right anglesthereto and such arm is of a length to engage the pegs85 and 86. Thegear reduction 89 rotates the output shaft 90 at a slow rate of speedfor a purpose which will be hereinafter described.

The crank arm 48 is provided with a cam 94 projecting inwardly towardthe gear box 46 and located on the opposite side of the shaft 47 fromthe slot 49. When the crank arm is rotated to advance or retract theshaft 23, the cam 94 will engage microswitches 95 and 96 mounted on thegear box 46. The microswitches 95 and 96 are located in a position suchthat the cam 94 will engage one of the switches as the shaft 23approaches the outermost limit or throw and will engage the other micro.

' be advanced a short distance more rapidly than normal when one of theswitches is closed and will be moved in the opposite direction counterto the movement of chain 32 when the other microswitch is closed. Themovement of the polishing head will form substantially a plur-ality ofspaced parallelograms due to the fact that the sprocket 80 is moving thechain and the sleeve 26 at a very slow rate of speed in one directionwhile simultaneously the motor 45 is extending and retracting the shaft23 back and forth across the stone being polished and as the polishinghead approaches one side of the stone the motor 41 is operated in onedirection to advance the sleeve in the same direction as the chain ismoving, and is operated in the opposite direction at the other side ofthe stone to move the sleeve in reverse direction counter to themovement of the chain.

In order to reverse the direction of travel of the sleeve 26 after ithas travelled the length of the stone, a limit switch 97 is mounted oneach of the posts 28 in a position to be engaged by one of the stops 42.Such limit switches are adapted to reverse the motor 87 to move thechain in the opposite direction. Since the ends of the stone do not havethe benefit of the full width of the polishing wheel, it is desirable toincorporate a delay in the machine so that the polishing wheel will moveback and forth across the ends of the stone without any longitudinalmovement. This is accomplished by locating the pegs 85 and 86 in anydesired opening 84 so that when the motor is reversed the arm 91 willmove away from the peg which it had been engaging and will operatefreely until it engages the other peg whereupon the sprocket 80 will beoperated in the reverse direction.

If desired, the pegs 85 and 86 may be removed from the sprocket 80 andthe sleeve 26 may be moved along the tubular member 27 by the motor 41as described in the first modification during the grinding process.During the polishing or buffing process the procedure of the secondmodification may be followed to impart the most desirable pattern ofmovement to the grinding or polishing wheel.

As illustrated in FIGS. 16 and 17 the grinding or polishing wheel 12 maybe rotated by a self-contained unit attached to the structure whichmoves along the length of the stone. In FIG. 16 such wheel is connectedby brackets 100 to a yoke 101 fixed to a shaft 102 and directly drivenby a motor and gear reduction 103. The motor and gear reduction aresecured to the bracket 53 at the outer end of the shaft 23 and aresupported by the grinding or polishing wheel which engages the stone.

In FIG. 17 a drive motor 105 is mounted on a bracket 106 depending fromthe inner end of the shaft 23 and such motor drives a multiple sheavepulley 107 which in turn drives a multiple sheave pulley 108 by belts109. The driven pulley 108 is fixed to a shaft 110 journaled in bearings111 mounted on the brackets 53 on the outer end of the shaft 23. Agrinding or polishing wheel is adapted to be fixed to the lower end ofthe shaft 110 in any desired manner.

It will be apparent from the foregoing that an automaticsurface-treating machine is provided in which the work unit is mountedso that it may be located in a position to allow access to the workarea, and also it is mounted for movement crosswise and lengthwise ofthe surface being treated and caused to pause at the limit of eachmovement, resulting in edge treatment greater than the intermediateportion of the object, the construction and arrangement making itpossible for a number of machines to be attended by one workman.

It will be obvious to one skilled in the art that various changes may bemade in the invention without departing from the spirit and scopethereof and therefore the invention is not limited by that which isillustrated in the drawings and described in the specification, but onlyas indicated in the accompanying claims.

What is claimed is:

1. An automatic surface-treating machine comprising a work head,mounting means for said work head comprising a first tubular shaftconnected by a universal joint to received within one of said sleeves, asecond tubular shaft extending through the other of said sleeves, spacedposts supporting said second shaft, sprockets at the opposite ends ofsaid second shaft, a chain mounted on said sprockets and extendingthrough said posts, spaced adjustable projections on said chain forengaging said posts, gearing carried by said platform and engaging saidchain, a reversible motor on said platform connected to drive saidgearing and move said platform and work headalong the work, controlmeans for reversing said motor when the work head reaches the end of thework, a second motor mounted on said platform, a crank having aconnection with the shaft of said motor, a connecting rod having one endadjustable relative to said crank, a bracket connecting the otherend ofsaid connecting rod to said first tubular shaft whereby upon operationof said crank by said second motor said connecting rod and first shaftwill be reciprocated relative to said platform.

2. A polishing unit of the floating head type, comprising a work head, ashaft having a ball and socket connection with said unit, a fittingreceiving said shaft, a platform attached to said fitting, a sleeveattached to the side of said platform at right angles to said fitting, atubular member received in said sleeve, posts mounting said tubularmember, sprocketed spaced end bars carried by said tubular member, achain extending around said sprocketed end bars, gearing engaging saidchain for moving saidplatform and work head, a reversing motor on saidplatform connected to drive said gearing, means for reversing saidmotor, spaced stops adjustably mounted on said chain allowing said motorto move said chain until one of said stops strikes an obstruction andupon con- 3. The structure of claim 2 in which said means for producingrecpirocation includes a second motor mounted on said platform, a crankarm driven by said motor, and a connecting rod and a bracket attached tosaid shaft for causing reciprocation thereof. I

4. The structure of claim 2 and means for supporting said work headcomprising an upright bar, a horizontal bar mounting said upright bar, apost, means mounting said horizontal bar for vertical adjustment on saidpost, and means for raising and lowering said horizontal bar on saidpost.

5. A machine for polishing the surface of objects, including stone,comprising a tank for containing a fluid and a stone or other object tobe polished, a work head of a character to be moved over the surface ofthe stone, and mounting means for said work head, said mounting meanscomprising a first shaft having a universal connection with said workhead, a support having a sliding moving said first shaft relative tosaid support, means for reversing said driving means, and meansproviding a delay in the movement of said work head when said drivingmeans is reversed, whereby said work head may be moved in a generallyhorizontal plane in two directions with a pause at the limit of eachmovement.

6. The structure of claim 5, and means whereby said work head may besupported in lowered operative position or in elevated position to allowaccess to the work area into and from a position to be operated upon bysaid work head.

7. The structure of claim 5, and means for supporting said work head forelevational adjustment.

8. An automatic surface treating machine comprising a work unit, meansfor supporting and driving said work unit, means automatically formoving said work unit over the surface of an object to be treatedincluding a support disposed along one side 'of the object, a sleeveslidably mounted on said support, a platform fixed to said sleeve, chainmeans having lost motion means carried by said support, a firstreversible drive means mounted on said platform and engageable with saidchain means for moving said platform along said support, a shaftslidably mounted on said platform and being reciprocable in a directiongenerally normal to the direction of movement of said sleeve, a seconddrive means mounted on said platform and having a crank arm, and aconnecting rod pivotally connected at one end to said crank arm andpivotally connected at the opposite end to said shaft.

9. The structure of claim 8 including a third drive means mounted onsaid support and engageable with said chain means, and means for drivingsaid first drive means intermittently in opposite directions;

10. A surface treating machine comprising an elongated member, aplatform slidably and rotatably mounted on said elongated member, afirst drive means for moving said platform along said elongated member,means for reversing said first drive means, means providing a delay inthe movement of said platform when said first drive means is reversed,shaft means slidably mounted on said platform at an angle to thelongitudinal axis of said elongated member, a tool carried by said shaftmeans, a second drive means for moving said shaft means relative to saidplatform, means for reversing the direction of movement of said shaftmeans, means providing a pause when the direction of movement of saidshaft means is reversed, and said first drive means and said seconddrive means being operated simultaneously or independently, whereby saidtool may be moved in multiple directions with a pause at the end oftravel in each direction.

References Cited by the Examiner UNITED STATES PATENTS 1,914,413 6/1933Elbert 5l35 2,694,274 11/ 1954 McGibbon 51-35 2,924,768 2/1960 Ferrandet al. 318-480 3,026,653 3/1962 Zordo 5l177 ROBERT C. RIORDON, PrimaryExaminer.

J. A. MATHEWS, Assistant Examiner.

1. AN AUTOMATIC SURFACE-TREATING MACHINE COMPRISING A WORK HEAD,MOUNTING MEANS FOR SAID WORK HEAD COMPRISING A FIRST TUBULAR SHAFTCONNECTED BY A UNIVERSAL JOINT TO SAID WORK HEAD, A PLATFORM, SLEEVESATTACHED TO SAID PLATFORM AT RIGHT ANGLES TO EACH OTHER, SAID FIRSTSHAFT SLIDABLY RECEIVED WITHIN ONE OF SAID SLEEVES, A SECOND TUBULARSHAFT EXTENDING THROUGH THE OTHER OF SAID SLEEVES, SPACED POSTSSUPPORTING SAID SECOND SHAFT, SPROCKETS AT THE OPPOSITE ENDS OF SAIDSECOND SHAFT, A CHAIN MOUNTED ON SAID SPROCKETS AND EXTENDING THROUGHSAID POSTS, SPACED ADJUSTABLE PROJECTIONS ON SAID CHAIN FOR ENGAGINGSAID POSTS, GEARING CARRIED BY SAID PLATFORM AND ENGAGING SAID CHAIN, AREVERSIBLE MOTOR ON SAID PLATFORM CONNECTED TO DRIVE SAID GEARING ANDMOVE SAID PLATFORM AND WORK HEAD ALONG THE